Abstract
Purpose :
Oxidative stress plays a key role in age-related macular degeneration (AMD) and retinitis pigmentosa (RP) pathogenesis as well as in several other eye diseases. Blue light (BL) exposure is one possible cause of increased production of reactive oxygen species (ROS) in retinal cells and might therefore be a promising non-chemical-based inducer of oxidative stress. We established a BL induced degeneration model on ex vivo porcine retinal explants and demonstrated that BL induces p53- dependent neurodegenerative processes in the retina.
Methods :
Whole pig eyes were exposed to BL (452nm) and cultivated for 24h. Afterwards, dead cells were stained with TUNEL and cell death was evaluated. Retinal organ cultures were exposed to BL in varying intensities and exposure numbers. Afterwards, the induced downstream mechanisms were analysed via immunohistology, western blot and qRT-PCR. Oxidative stress as well as the apoptotic state of the retinal explants was determined. BL exposed retinal explants were treated with 1µM p53 inhibitor Pifithrin α to evaluate p53-dependency.
Results :
Significantly more dead (TUNEL+) retinal cells were found in whole pig eyes exposed to BL (+280%). BL significantly induced oxidative stress levels in the retinal explants, depending on the duration and repetition of exposures. Especially Müller cells and Photoreceptors reacted very sensitive to BL, as observed by strong increase of GFAP levels and decreased Rhodopsin expression. Exposed explants demonstrated significant higher levels of cell death markers like TNF-α, TUNEL+ cells and caspase 3/7 activity compared to untreated controls. Additional apoptotic marker expression, like BAX and modified p53, was increased due to BL exposure. Inhibition of p53 after exposure resulted in less oxidative stress and enhanced retinal survival.
Conclusions :
An oxidative stress based retinal model with induced neurodegeneration was successfully established. It could be demonstrated, that BL is able to reach the retina through the whole eye and induce cell death. Furthermore, apoptotic induction as well as p53 dependency was demonstrated in our ex vivo model. This model can be used to further analyse and understand oxidative stress-based cell death in retinal cells and to test therapeutic approaches for AMD- or RP treatment ex vivo.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.